Computational haemodynamics analysis and comparison study of arterio-venous grafts

Haemodialysis arterio-venous graft failure is related to the development of stenotic lesions most commonly located near the venous anastomosis, especi ally in the toe region. 'Disturbed flow' interaction with the vessel wall s urface, characterized by haemodynamic parameters based on the local wall sh eer stress or the radial pressure gradient, have been widely recognized as the trigger mechanism of a cascade of abnormal biological events leading to occlusive developments Assuming incompressible laminar flow and rigid, in- plane vessel walls, validated haemodynamics are numerically simulated for a constant-diameter end-to-side base case, the Venaflo(TM) graft, and an imp roved graft-end configuration. The geometric design of the new graft-end wa s based on the reduction of three time- and area-averaged haemodynamic para meters, i.e. the wall shear stress gradient, wall shear stress angle gradie nt, and radial pressure gradient. Considering the critical toe region, the Venaflo(TM) graft has demonstrated measurable improvements over the base ca se configuration in predictive computer simulations as well as in clinical trials. The performance improvement should be further enhanced with the mod ifications illustrated bg the new design.